Q1. Which of the following acids is commonly found in citrus fruits such as oranges and lemons?
a) Hydrochloric acid
b) Sulfuric acid
c) Citric acid
d) Acetic acid
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Correct Answer: c) Citric acid
Explanation: Citric acid is a weak organic acid found naturally in citrus fruits such as oranges, lemons, limes, and grapefruits. It is responsible for the sour taste of these fruits and is widely used as a flavoring agent in food and beverages. Citric acid is also used as a preservative to extend the shelf life of foods and as an acidulant to adjust the acidity of products. In addition to its culinary uses, citric acid has applications in household cleaning products, personal care items, and pharmaceuticals.
Q2. Which acid is commonly used in the production of fertilizers and detergents and is known for its corrosive properties?
a) Hydrochloric acid
b) Nitric acid
c) Sulfuric acid
d) Phosphoric acid
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Correct Answer: c) Sulfuric acid
Explanation: Sulfuric acid, also known as oil of vitriol, is a strong mineral acid with the chemical formula H2SO4. It is one of the most widely used acids in industry and is primarily used in the production of fertilizers, detergents, explosives, and chemicals. Sulfuric acid is highly corrosive to metals, organic materials, and living tissues and must be handled with extreme caution. It is produced in large quantities through the contact process, which involves the oxidation of sulfur dioxide to sulfur trioxide, followed by the hydration of sulfur trioxide to form sulfuric acid.
Q3. Which acid is commonly found in vinegar and is used in food preservation, cooking, and pickling?
a) Hydrochloric acid
b) Nitric acid
c) Citric acid
d) Acetic acid
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Correct Answer: d) Acetic acid
Explanation: Acetic acid, also known as ethanoic acid, is a weak organic acid with the chemical formula CH3COOH. It is commonly found in vinegar, which is a diluted solution of acetic acid produced through fermentation of carbohydrates by acetic acid bacteria. Acetic acid is widely used in food preservation, cooking, and pickling to impart a sour flavor and inhibit the growth of spoilage microorganisms. It is also used in the production of various chemicals, solvents, and plastics, as well as in household cleaning products and personal care items.
Q4. Which acid is a component of gastric juice in the stomach and plays a crucial role in digestion?
a) Hydrochloric acid
b) Sulfuric acid
c) Nitric acid
d) Phosphoric acid
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Correct Answer: a) Hydrochloric acid
Explanation: Hydrochloric acid (HCl) is a strong mineral acid that is a component of gastric juice in the stomach. It is produced by parietal cells in the gastric glands and plays a crucial role in the digestion of food. Hydrochloric acid helps to denature proteins, activate enzymes, and kill ingested microbes, creating an acidic environment that facilitates the breakdown of food molecules into smaller, absorbable components. Despite its corrosive nature, hydrochloric acid is essential for proper digestion and nutrient absorption in the gastrointestinal tract.
Q5. Which acid is commonly used in the manufacturing of explosives, fertilizers, and nitrate salts?
a) Acetic acid
b) Nitric acid
c) Citric acid
d) Phosphoric acid
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Correct Answer: b) Nitric acid
Explanation: Nitric acid (HNO3) is a strong mineral acid used in the manufacturing of explosives, fertilizers, and nitrate salts. It is produced industrially through the Ostwald process, which involves the oxidation of ammonia to nitrogen dioxide, followed by the absorption of nitrogen dioxide in water to form nitric acid. Nitric acid is a versatile chemical with applications in various industries, including agriculture, pharmaceuticals, metallurgy, and electronics. It is also used in the production of dyes, plastics, and rocket propellants, as well as in etching and metal cleaning processes.
Q6. Which acid is commonly used in the soft drink industry to impart a tangy flavor and act as a preservative?
a) Hydrochloric acid
b) Sulfuric acid
c) Phosphoric acid
d) Nitric acid
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Correct Answer: c) Phosphoric acid
Explanation: Phosphoric acid (H3PO4) is a weak mineral acid commonly used in the soft drink industry to impart a tangy flavor and act as a preservative. It is added to carbonated beverages such as cola drinks to provide acidity and enhance taste perception. Phosphoric acid also serves as a chelating agent, stabilizer, and acidulant in various food and beverage products. Despite its acidic properties, phosphoric acid is generally recognized as safe (GRAS) for consumption in small quantities and is approved for use in food by regulatory agencies worldwide.
Q7. Which acid is commonly used in the photography industry for developing photographic films and prints?
a) Acetic acid
b) Hydrochloric acid
c) Sulfuric acid
d) Citric acid
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Correct Answer: a) Acetic acid
Explanation: Acetic acid (CH3COOH) is commonly used in the photography industry for developing photographic films and prints. It is a key component of the developer solution, which converts the latent image formed on the photographic emulsion into a visible image. Acetic acid acts as a solvent, facilitating the reduction of exposed silver halide crystals to metallic silver.
Q8. Which acid is commonly used in the production of batteries, detergents, and textile processing?
a) Sulfuric acid
b) Nitric acid
c) Citric acid
d) Acetic acid
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Correct Answer: a) Sulfuric acid
Explanation: Sulfuric acid (H2SO4) is a strong mineral acid widely used in industrial processes such as battery manufacturing, detergent production, and textile processing. It is one of the most important chemicals produced worldwide, with applications in various sectors, including metallurgy, mining, petroleum refining, and wastewater treatment. Sulfuric acid is used as a catalyst and reactant in numerous chemical reactions, including the production of fertilizers, explosives, synthetic fibers, and pharmaceuticals. Its corrosive nature and acidic properties make it a versatile and indispensable chemical in modern industry.
Q9. Which acid is commonly used in the leather industry for tanning hides and skins?
a) Hydrochloric acid
b) Nitric acid
c) Formic acid
d) Sulfuric acid
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Correct Answer: c) Formic acid
Explanation: Formic acid (HCOOH) is commonly used in the leather industry for tanning hides and skins. It is a weak organic acid derived from the oxidation of methanol and is known for its preservative and antimicrobial properties. Formic acid penetrates the collagen fibers of animal hides, stabilizing them and preventing decomposition. This process, known as tanning, transforms raw hides into leather, imparting durability, flexibility, and resistance to decay. Formic acid is also used in other industrial applications, including textile processing, rubber manufacturing, and animal feed preservation.
Q10. Which acid is commonly used in the manufacturing of soap, biodiesel, and pharmaceuticals?
a) Oleic acid
b) Lactic acid
c) Formic acid
d) Butyric acid
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Correct Answer: a) Oleic acid
Explanation: Oleic acid is a monounsaturated omega-9 fatty acid commonly used in the manufacturing of soap, biodiesel, and pharmaceuticals. It is derived from natural sources such as olive oil, sunflower oil, and animal fats. Oleic acid is valued for its emulsifying, moisturizing, and cleansing properties, making it a key ingredient in soap and cosmetic formulations. In biodiesel production, oleic acid is converted into fatty acid methyl esters through transesterification, yielding a renewable and environmentally friendly fuel source. Oleic acid also has pharmaceutical applications, including as an excipient in drug formulations and as a precursor for the synthesis of various pharmaceutical compounds.